不同耕作方式下全膜双垄沟播玉米农田氮素转化与气态损失的效应与机制

全膜双垄沟播技术是黄土高原玉米生产重要的种植技术，目前该技术下土壤氮素转化机理研究欠缺，且在生产中存在土壤氮素大量残留、气态损失(N2O 排放和NH3挥发)严重和肥料利用效率偏低等问题。耕作方式能影响肥料利用效率，研究不同耕作方式下全膜双垄沟播玉米氮素转化与气态损失效应与机制具有重要的生产指导意义。本项目立足于黄土高原全膜双垄沟播玉米生产实际，设置不同耕作方式(翻耕、旋耕和深松耕)，利用15N 同位素示踪和高通量测序等技术，研究不同耕作方式下连续三季作物对肥料氮吸收利用情况，及肥料氮素在土壤残留的时空变化，分析土壤氮素转化过程中氮功能微生物群落丰度和多样性变化，结合不同耕作方式下土壤理化性质、酶活性和氮素气态损失规律，构建结构方程模型，探究耕作方式调控全膜双垄沟播玉米农田氮素转化和气态损失的作用机制，揭示全膜双垄沟播农田土壤氮素转化的微生物机理，为该地区制定合理的氮肥管理策略提供理论支撑。

Double ridges and furrow mulched with plastic-film is wild used in corn planting in Loess Plateau. Up to now, the mechanism of nitrogen transformation in this planting technique is lack, nitrogen residual in soil and gaseous loss are serious, fertilizer use efficiency is reletive low. Tillage method have significently effects on fertilizer use efficiency, it will be useful to study the effect of tillage method on nitrogen transformation and gaseous loss in corn planting with double ridges and furrow mulched with plastic-film. This study was conducted with three treatment(plowing, rotary tillage and subsoiling), using methord of 15N-labeling, static closed chamber/GC technique and high-throughput sequencing, to study the use of urea by plant and change of nitrogen residual in soil, analyze the change of the nitrogen function microbial community structure and abundance composition in process of nitrogen transformation, combined with the soil physical and chemical properties, enzyme activity and gaseous losses of nitrogen under different tillage method, constructing a structural equation model, revealing the mechanism of nitrogen transformation, rule of gaseous losses, and the role of microbial community. The result of this study will provide theoretical support for the improvement of nitrogen management in Loess Plateau.